Road grader



Aug. 15, 1933- F. L. CARSWELL ET AL ROAD GRADER Filed April 25, 19:52

INVENTORS, ZI/W/a'w L tars/rail ATTORNEYS.

Patented Aug. 15, 1933 PATENT OFFICE ROAD GRADER Firman Carswell and Otto W. Schmidt, Kansas City, M0.

Application April 25, 1932. Serial No. 607,247

9 Claims.

This invention relates to road graders, and particularly to that type of grader comprising a vehicle having a vertical, adjustable grading member mounted thereon and means for adjusting andholdingthe grading member in a predetermined position during the operation of the device.

Much diiliculty has been experienced in the operation of road graders of this'class, due to the fact that when the grading member or blade has been set to a position relative to the frame of the vehicle and the grader is then operated, there is a resultant vibration or chatter of the blade which is transmitted to the blade control parts, so that these parts will creep in the direction of greatest torque, thereby disadjusting the blade. This difiiculty, has been experienced in the screw feed type of blade control mechanism, as well as the worm and worm gear type, as shown in this invention.

When the blade is in the position for grading and is movediorward in the usual manner, it will chatter or vibrate to a degree depending on the irregularity of the structure being graded. This vibration is transmitted to the vertical control mechanism for the blade and parts which would normally interlock and maintain the blade in a fixed position are caused to creep, due to the slight vibratory movement of the interconnecting parts.

Under these circumstances, the greater torque on the interconnecting parts would be such that the blade would be normally raised. When the blade is in the inoperative position, that is, raisedfrom contact with the surface and the grader is being transported, the blade will gradually lower, since the weight of the parts will exert a torque against the interlocking parts in the opposite direction from that exerted when the blade is in the operative position.

The principal object of this invention is toovercome these difficulties by associating with the blade operating means, a vibration or chatter-absorbing element, which will operate to maintain the grading member in a predetermined relative position.

A further object of this invention is the provision of a road grader having a vertical, adjustable grading member; means including a gear reducing unit for raising and lowering said grading member, and a vibration absorbing element associated with said raising means whereby the grading member is maintained in a predetermined, adjusted position. V

A still further object of the present invention is to provide an automatic vibration absorbing element for the purpose intended, which will preclude accidental movement of the supported element, but which will permit of easy adjustment of the blade through the controlling mechanism.

Further objects of this invention are simplicity, economy of manufacture, and adjustability to meet varying load conditions.

Referring to the drawing:

Figure 1 is a side elevation of a road grader, partially broken away and including the present invention. a

2 is an enlarged elevation partly in section, of a portion of the blade lifting mechanism.

Fig. 3 is an enlarged, central, sectional view including the vibration absorber.

Fig. 4 is a fragmentary, inverted, plan view of the parts shown in Fig. 3.

Fig. 5 is an enlarged, sectional view line VV of Fig. 2.

Fig. 6 is a face view of the stationary disc of the vibration absorber, and,

Fig. '7 is a face view of the rotatable disc taken on the vibration absorber member. 0

self-propelled over surfaces to be graded. Loose- 1y mounted at its forward end in the usual manner, is a frame 16, which is adapted to carry a grading tool such as a blade 18. This blade may be supported and controlled in such a manner as to permit or" substantially universalmovement of the same. However, the vertical, or up and down movement of the frame 16, together with blade 18, is the movement with which this invention is most concerned.

Securely mounted on body 12 is a housing 20, in which is rotatably mounted a shaft 22, to which is fixed a segmental worm gear 24. Carried by housing 2e and in operative relation with worm gear 24, is a worm 26, fixed to a rotatably mounted shaft 28 which may be provided with the usual anti-friction bearings. Shaft 28 may be rotated either manually or by power, and when so rotated, willralso rotate worm 26 to oscillate segmental gear 24. The direction of rotation of gear 24 can be. predetermined bythe direction of rotation of shaft 28.

A convenient and practical means for rotating shaft 28 is shown in Fig. 2, and consists of a hand wheel 30, rotatably mounted on a shaft 32, which in turn is operatively connected by means of a pair of beveled gears 34 to shaft 36, which is joined to shaft 28 through the inter mediary of a universal joint 38. that hand wheel 35 might be directly positioned on shaft 28 to produce rotary motion thereof. Shaft 22 extends through housing 20 and has securely affixed to its extended end, a lever 40. Lever 40 is interconnected with frame 16. through the intermediary of link 42 in such a manner that when Worm gear 24 is oscillated, frame 16 will be moved in a substantially vertical direction.

It is apparent that the blade lifting mechanism just described may be operated by simply rotating hand wheel 30 to either raise or lower the.

grading member. Furthermore, it is imperative that when the blade has been adjusted to a predetermined position, that it be held in said position and not be permitted to move in either direction relative to the body of the grader, and it is to insure this permanent positioning of the blade that the following device is applied in the manner described.

' Mounted loosely on shaft 28 adjacent housing 20 is a disc 44, having a bifurcated lug 46 which is adapted to span a stationary lug 48, carried by the bodyof the grader. The outer face 50 of disc 44 is radially grooved to substantially register with grooves 52, formed in the face of disc 54, which is securely attached concentrically to shaft 28 by means of a pin 56. Positioned between disc 44 and housing 20, is a spring 58, under compression. The amount of compression of spring 58 may be varied by positioning pin 56 in the different corresponding grooves 60 or castellations formed in theouter surface of disc 54. It will be noted, by referring to Fig. 4, that the side walls of the grooves and resultant ridges formed on the adjacent faces of discs 44 and 54 are uniformly inclined, thereby producing like resistance to the shaft 28 when the same is rotated in either direction.

This vibration or chatter absorbing element just .clescribed-operates in the following manner: When blade 18 is caused to vibrate or chatter during its operation, the vibratory movement is transmitted to link 42, lever 40, shaft 22, to gear 24, thus causing the teeth of said gear to vibrate so as to contact first one side and then the other of the thread of worm 26. Due to the angularity of the teeth and thread, this action causes the worm 26 andshaft 28 to oscillate through a slight angle in the direction of the greatest torque.

When shaft 28 is so oscillated, the discs 44 and 54 will be forced apart to a slight degree and certain of the adjacent, inclined surfaces of the discs will remain in contact so that when the direction of the vibration is reversed, the disc, due to the action of spring 58, will again come together to a normal seated position. Due to the differential of gear 24 and worm 26, oscillation of disc 54 is very slight and it is only necessary that the pitch of the grooves or teeth formed on the disc be of sufficient dimension to preclude a possible ratcheting of one set of teeth into the next adjacent grooves. By means of this vibration absorbing element, it is apparent that while the shaft 28 may vibrate to a certain degree, it will not permit the movementof the blade from'the predetermined, adjusted position to any material degree. All forward movement of the shaft 28 toward the direction of greatest torque will be compensated It is apparent for at the rebound by the action of the vibration absorbing element.

While this vibration absorbing element has been shown on but one type of grading machine, yet it is apparent that it may be applicable to any road grader or similar machine wherein a vertical, adjustable weight is carried by a vehicle and is provided with means whereby'it is raised or lowered to a predetermined, operative position.

What we claim is:

. 1. In a road grader of the class described, a vertically adjustable grading member; means, including a gear reduction, to raise and lower said grading member; and a vibration absorber having intermeshing, inclined surfaces associated with said means whereby said grading member is secured against accidental disadjustment.

2. A road grader comprising a vehicle having a frame, a blade carrying frame connected at one of its ends to said vehicle frame; an operating shaft carried by said vehicle frame; means, including a speed reducing gear, connecting said shaft with the free end of said frame; and an over-riding vibration absorber associated with said shaft, whereby the blade carrying frame is secured against accidental movement relative to said vehicle frame.

3. A road grader comprising a vehicle having aframe, a blade carrying frame connected at one of its ends to said vehicle frame; a manually operable shaft rotatably' mounted on said vehicle; an over-riding vibration absorber associated with said shaft and vehicle frame; and

speed reducing means interconnecting said shaft and the free end of said frame whereby when said shaft is rotated said frame will be moved in a vertical direction.

7 4. A road grader comprising a vehicle having a frame;- a vertically adjustable grading member carried by said vehicle frame; a gear reduction unit mounted on said vehicle frame; means connecting said grading member with the low speed side of said gear reduction unit; manually operable means connected with the high speed side of said gear reduction unit; and a brake, having intermeshed discs resiliently held together and associated with said manually operable means and said vehicle frame respectively, whereby the gear reduction means is secured against accidental disadjustment.

5. In a road grader of the class described, a vertically adjustable blade; means for raising and lowering said blade; and a vibration absorber, having interengaging serrated surfaced discs, associated with said raising means to prevent accidental disadjustment of said grading member;

6. In a road grader of the class described, a vertically adjustable grading member; means, including a gear reduction, to raise and lower said grading member; including a rotatably mounted toothed disk interengaging the teeth of a non-rotatably mounted disk, and associated with said raising and lowering means whereby said grading member is secured against accidental disadjustznent.

7. In a road-grader, a wheel supported main frame; a tool carrying frame pivoted at its front end to the main frame; means, including a gear reduction unit, to vertically adjust said tool carrying frame; and a vibration absorber including a toothedimember movable with said adjusting means, a toothedmember secured to frame; a tool carrying frame pivoted at one of its ends to the main frame; means for vertically adjusting said tool carrying frame; a rotatably mounted shaft; a toothed disk securely attached to said shaft; a toothed disk loosely mounted on said shaft for longitudinal movement thereto; means carried by said main frame to engage said second named disk to preclude rotary movement thereof; and a. resilient member to normally maintain the teeth of said disks in intermeshed operative relation.

FIRMAN L. CARSWELL.

OTTO W. SCHMIDT. 

